Don't know if it's possible or not, because I've not seen any of the major sites doing it.
Basically, I have an ezine with two different editions, a European and North American. Is it possible to only present subscribers with a drop-down box asking which state/province they reside in if they select the North American edition? Obviously it's meaningless to ask them which state they reside in if they live outside the US/Canada.
I know there could just be an option in the state/province drop-down form which says 'N/A', but I thought removing the drop-down box if they state they live outside North America would be cool :)
How does one integrate such a feature into a sign-up form?